Canada



May 8, 1923. 1,454,344

I t R. H. STEWART I SOLIDIFYING MOLTEN SULPHUR Filed May 27, 1920 -2 Sheets-Sheet 1 Patented May 8, 1923.

ROBERT HOLDEN STEWART, OF VANCOUVER, BRITISH COLUMBIA, CANADA, ASSIGNOR TO TEXAS GULF SULPHUR COMPANY, OF BAY CITY, TEXAS, A CORPORATION OF TEXAS.

SOLIDIFYING MOLTE'N SULPHUR.

Application filed May 27, 1920. Serial No. 384,607.

To all whom it may concern:

Be it known that 1, ROBERT H. STEWART, a subject of Great Britain, residing at Vancouver, British Columbia, Canada, have invented certain new and useful Improvements in Solidifying Molten Sulphur; and I do hereby declare the following to be a full, clear, and exact descriptionof the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to the solidification of molten sulphur, and has for its object the provision of an improved method of and apparatus for solidifying molten sulphur. More particularly, the invention relates to improvements in the production of sulphur by underground fusion with the discharge of molten sulphur at the surface of the ground, and in this Connection the invention aims to provide a practical method of and apparatus for solidifying the molten sulphur in a physical form suitable for handling and transportation fro-m the sulphur fields to the consuiners.

In the production or mining of sulphur by underground fusion in accordance with the well known Frasch process, a fusing fluid, such as superheated water under pres sure, is 'conveyed to the underground sulphur deposit where its heat is utilized in fusing the sulphur and the fused sulphur is raised to the surface of the ground in a' molten condition by suitable agencies such, for example, as an air lift pump. The satisfactory disposition of the molten sulphur as it is discharged at the surface of the ground from the so-called sulphur wells presents certain peculiar difiiculties. At the present time, it is the customary.--practice to solidify the sulphur in the form of-a huge,v

. block or pile often containing many thousands of tons of sulphur. Thus, in accordance with the present prevailing practice, the molten sulphur is conveyedfrom the sulphur wells to a bin made up of four enclosing Walls extending an appropriate distance above the ground level. The enclosing walls are frequently several hundred feet in length and,-as previously mentioned, are

designed to hold or enclose a huge quan-..

tity of sulphur. The molten sulphur flows into this enclosure and eventually solidifies into a huge block of the dimensions of the enclosing walls; In actual practice, many weeks and frequently months elapse before this block of sulphur becomes solid throughout its entire mass.

The pile or block of sulphur, formed as above described, must be broken up for the subsequent handling and shipment from the sulphur field to the consumers. To this end, it is necessary to blast the sulphur pile in substantially the same manner that rock is blasted. Byrepeated blasting and considerable manual labor, the sulphur is finally prepared for loading, usually by automatic loading machinery, into freight cars or other vehicles of transportation. The present "practice of solidifying the molten sulphur thus involves the formation of a huge pile of solid sulphur and-subsequently breaking up this pile of sulphur into suitable size for handling and transportation. Moreover, the present practice necessitates the provision above ground of a very large quantity of sulphur, since while one pile or block of sulphur is being broken down and shipped, another block must be in progress of building, and on this account many thousands of tons of sulphur must be constantly maintained above ground. This is, of course, an uneconomical procedure, and it is desirable that some satisfactory method of solidifying sulphur be provided by which the sulphur is prepared for shipment within a very short time after it is discharged from the sulphur mines, thereby reducing to a minimum the amount-of sulphur which must be allowed to accumulate above ground.

The present invention aims to provide a method of and apparatus for solidifying molten sulphur as rapidly as it is discharged from the sulphur mines in a continuous manner and in sizes and shapes suitable for subsequent handling and transportation.

Thus, in accordance with the method of the invention, the molten sulphur from the" plurality of operatively connected pan-like units, each unit having a plurality of pockets. In feeding themolten sulphur to the travelling conveyor, the pockets of each unit are allowed to become so filled that the molten sulphur overflows the pockets and forms a relatively thin layer of sulphur overlaying all of the sulphur-filled pockets of the conveyor unit. The travelling eonveyor is preferably subjected to the action of an artificial cooling medium, such, for example, as a trough of cold water through which the pan conveyor may be moved so as to cool the bottoms and side walls of the pockets. If desired, a cooling medium may be blown or otherwise appropriately projected against the top surface of the sulphur in the travelling conveyor.

As a result of filling the conveyor units so that a thin layer of sulphur overlays all of the pockets of each conveyor unit, all of the sulphur-filled pockets of each conveyor unit are connected together by this overlaying sheet or layer of sulphur, and this connection between the cakes of sulphur assists in clearing the pockets, since shrinkage pulls the sulphur cakes loose and the weight of the whole mass of sulphur in the conveyor unit loosens up any individual cakes which tend to stick to the pockets. lln dropping from the conveyor units, the sulphur cakes break apart into convenient sizes for subsequent handling.

The conveyor units are preferably made of metal, for example, sheet iron. Molten sulphur sticks tenaciously to a dry iron surface, but I have found that if the sulphurcontacting surfaces ,of the conveyor units are moistened with an appropriate fluid, such, for example, as a film of water, the sulphur will not stick to the pockets of the conveyor unit, and for this reason I apply.

to the sulphur-contacting surfaces of the conveyor units a film of water prior'to the feeding of molten sulphur into the conveyor units.

. ll have found that the length ofthe travelling conveyor can be materially shortened if the cakes of sulphur are discharged therefrom before they have become entirely solid throughout, and permitting the complete solidification of the sulphur cakes to takeplace on' a separate slowly-moving conveyor.

tinuous discharge of the sulphur cakes'from the ,travelling conveyor without objectionably breaking the cakes, and the complete solidification of the sulphur cakes takes place on a slowly moving conveyor, which,

ineaaaa 'mode of operation of apparatus embodying the same, will be understood from the following description taken in conjunction with the accompanying drawings, in which:

Fig. 1 is an elevation of an apparatus adapted for the practice of the invention;

Fig. 2 is a plan of the apparatus of Fig. 1

Fig. 3 is an enlarged elevation of the travelling conveyor of the apparatus of Fig. 1;

Fig. 4 is a sectional view taken on the section line 14 of Fig. 2; and

Fig. 5 is a sectional view taken on the section line 55 of Fig. 3.

The molten sulphur flowing from the sulphur wells is conveyed in its molten condition by any appropriate instrumentalities to a storage basin 10. The storage basin 1() may be constructed of any appropriate material suitable for holding molten sulphur, and may be built either above the ground or in the ground, although ll generally prefer to build the basin in the ground.

An elevated tank 11 is arranged 'to be supplied with molten sulphur from the storage basin 10 by means-of a pump 12. The level of the molten sulphur in the tank 11 is maintained constant by means of an overflow 13, so that the' molten sulphur in the tank 11 is always under a uniform static head. Pipes 14 convey the molten sulphur from the tank 11 to appropriate distributors 15. The distributors 15 are designed to feed the molten sulphur onto the travelling conveyor in a uniform and satisfactory manner for the purposes hereinafter described. The storage basin 10, tank 11, pump 12 and cooperating piping, pipes 14: and distributors 15 are provided with appropriate heat insulating means, or, if necessary, with appropriate steam jackets, in order to prevent chilling or solidifying of the molten sulphur, thereby insuring the feeding of the sulphur from the distributors 15 to the travelling conveyor in a satisfactory fluid or molten condition.

The travelling conveyor 16' of my improved sulphursolidifying apparatus is of the continuous pan-conveyor type and is composed of a plurality of panlike units 16. The conveyor units 16 are appropriately fastened. to the \links of the link belts 17. 'Wheels' l8-andtransverse axles 19 are operativelyassociated with the link belts, as will be well understood by those skilled in the pan-conveyor art. The ends 16" of adjacent conveyor units preferably overlap about the adjacent axle 19, as indicated in 4 sprocket wheels 23 and 23.

protect the axle from becoming coated with sulphur. A pair of upper rails 20 and a pair oflower rails 21, supported by a framework 22, are provided for engaging the wheels 18 and thereby operatively supporting the travelling conveyor.

The travelling conveyor is of the continuous type and at its ends engages cooperating .The sprocket wheel 23 is connected to an electric motor. 24 through a belt 35 and variable reduction gearing 25, and by this motive means and reduction gearing the conveyor may be driven at any desired speed.

' these pockets would then be about four inches square at the bottom.

The transverse axles 19 may conveniently be placed 24 inches apart, and the conveyor units 16 may conveniently be made about 42 inches in width, thus providing for each conveyor unit 16 three transverse rows of seven pockets each, making 21 pockets for each conveyor unit. The conveyor units may be made about four inches in depth,

that is the distance from the axle 19 to the bottom of the pockets 26.

The conveyor units 16, in travelling over their upper path, pass through a cooling medium, such as water, contained in a I positioned between the rails- 20 and beneath the conveyor units when travelling over their upper path. The rails 20 are turned upwardly at their ends, so as to properly guide the conveyor units into and out of the pan of water. The water in the pan may be-maintainedcool by circulation or in any other appropriate manner.

The complete casting apparatus illustrated in Fig. 2 of the accompanying draw ings is composed of three sections, each section containing a pair of travelling conveyors 16 arranged to discharge the sulphur cakes formed, therein onto a slow moving platform or conveyor 28. The three platforms 28 discharge onto a common belt conveyor 29. A chute 30 is provided for guiding the partially solidified cakes of sulphur from the conveyor 16? to the platform 28. Where the sulphur cakes display any tendency to stick to the pockets 26, the bottoms of the units 16 may be rapped with an air hammer having a large flat-faced hammer just after the units pass the sprocket 23. In order to catch any sulphur cakes thus dislodged from the conveyor, the platform 28 preferably extends a suitable distance beneath this end of the conveyor, and a shield orguide plate 31 may, if desi'red, be provided at the lower end of each platform 28.

The operation of the apparatus is sub-' stantially as follows. Molten sulphur under a substantially uniform and constant pressure is fed from the tank 11 through the distributors 15 into the conveyor units 16. Feeding of the molten sulphur to the travelling conveyor under a substantially uniform pressure is necessary in order to obtain proper regulation of the rate of feed, and in the apparatus represented in the drawing thisuniform pressure is secured by means of the elevated tank 11 which is kept overflowing by the combined action of the pump 12 and overflow 13, the overflowing sulphur returning to the storage basin 10.

The distributors 15 are provided with suitable valves for regulating the feed of molten sulphur.

Molten sulphur is fed into each conveyor unit 16, so as to overflow the pockets 26 and form a thin layer or sheet of sulphur overlaying all of the pockets of the conveyor unit. This overlaying layer of sulphur may be one-fourth to three-eighths of an inch in thickness, whereby the maximum depth of the sulphur in a conveyor unit of the dimensions hereinbefore given will be from one and one-quarter inches to one and .three-eighths inches. The individual cake of sulphur formed in the pockets of such a conveyor unit will weigh in the neighborhood of three pounds.

A cake of sulphur formed in a pocket of the dimensions hereinbefore mentioned Will, under the conditions prevailing in ordinary practice, completely solidify in about thirty minutes. I find that such a cake of sulphur will in about ten minutes solidify on its outside to a. suflicient extent to permit cop tinuous discharge of cakes of sulphur from the travelling conveyor without breaking of the partially solidified sulphur cakes and spilling of the molten sulphur in the-interior thereof. The sulphur solidifying apparatus is therefore operated so as to give the sulphur in the pockets 26 about ten minutes to solidify to a suflicient extentto permit the continuous discharge from the Where-the sulphur cakes are given about ten minutes to partially solidify in the pockets of the travelling conveyor, it will be obvious that a further twenty minutes, or more, will be required to complete the solidification of the sulphur cakes throughout their entire mass. In the apparatus of the present invention the further and complete solidification of the cakes of sulphur takes place on the platform conveyors 28. In order to assure the complete solidification of the cakes of sulphur, llpropose in practice to construct the platform conveyor 28 about sixty feet in length and to move this conveyor at a speed of about one foot per minute. The cakes of sulphur discharged from the travelling conveyor 16' will pile up to some extent on the platform conveyor 28, but will be maintained on the latter under appropriate cooling influences for a suflicient length of time to insure the complete solidification of the sulphur cakes.

lit will, of course, be understood that the dimensions hereinbefore mentioned have been given purely for the sake of illustration and are merely intended to indicate a construction of apparatus suitable for carrying out the invention. 1 do not, therefore, intend by the foregoing description to limit the invention to the size of apparatus and particular dimensions set forth.

The conveyor units 16 may advantageously be made of sheet iron or steel. If desired the sulphur-contacting surfaces of the conveyor units may be covered or otherwise protected by an appropriate agent for withstanding any corrosive action which molten sulphur might have thereon. ll find that the sticking of molten sulphur to the conveyor units can be effectively prevented by moistening the sulphur-contacting surfaces. of these units with water, prior to the feeding of molten sulphur thereto. To this end, water spraying pipes 32 are provided for spraying the pockets 26 with water-"while the, conveyor units are passing over their lower path. This spraying with water must be conducted in such a way that the sulphur-contacting surfaces of the conveyor units are moistened or covered with a film of water at the time the molten sulphur is introduced from the distributors 15 intothe conveyor units. When thus properly moistened with water, the sulphur will not stick to the bottoms or side walls of the pockets 26.

i As the conveyor units pass over the sprocket wheel 23, the contents of each unit is discharged onto the platform conveyor 28. The connection between the sulphur cakes formed by the overlaying sheet of sulphur assists in clearing the conveyor units of the sulphur therein, since, due to shrinkage of the mass of sulphur as a whole, the cakes of sulphur in the pockets are pulled loose, and the weight of the whole mass of sulphur in the conveyor unit loosens up any individual cakes of sul hur which tend to stick in the pockets. n dropping from the conveyor units. onto the platfrom conveyor 28, the sulphur cakes break apart into sizes convenient for subsequent handling. If it is desired to break up the sulphur cakes into smaller sizes, suitable crushing apparatus may be installed at the end of the belt conveyor 29.

The apparatus of the invention may ta vantageously be employed for solidifying molten sulphur from any source. owever, the principles of the invention are more particularly applicable to the production of sulphur by fusion underground with the discharge or delivery of molten sulphur at the surface of the ground. As applied to this method of producing sulphur, the present invention enables the rapid and convenient solidification of the molten sulphur delivered by the sulphur wells. The molten sulphur from these wells is thus conveyed while still in a molten condition to the storage basin 10 and is then expeditiously solidified in suitable physical form for subsequent handling and transportation without the necessity of storin above ground enormous quantities of sulphur as required by the present customary practice. Thus, in accordance with the present invention, the sulphur may be solidified and ready for shipment within a few hours after its delivery in a molten condition from the sulphur wells.

From the foregoing discussion, it will be recognized by those skilled in the art that this is a pronounced improvement over the customary practice of handling the molten sulphur delivered by the sulphur wells. The characteristic feature of the invention is the solidification of such sulphur, while still in a molten state, in relatively small thin cakes, and by that l mean cakes approximately one inch in thickness and not exceeding a maximum of about one and three-eighths inches in thickness.

ll claim:

1., The improvement in the production of sulphur by undergroundfusion with the discharge of molten sulphur at the surface of the ground, which comprises continuously forming the sulphur while still in a molten state into-aplurality of relatively small thin cakes, moving said cakes in a substantially continuous manner from the point of their formation to a discharge point, and allowing the cakes to at leastv partially solidify during said movement so as to permit their continuous discharge at saiddischarge point in substantially solid form.

2. The improvement in the production of sulphur by underground fusion with the discharge of molten sulphur atthe airfawe of till the ground, which comprises continuously forming the sulphur while still in a molten state into sets of relatively small thin cakes, the cakes of each set being interconnected by a thin layer of sulphur, moving said cakes in a substantially continuous manner from the point of their formation to a discharge point, and allowing the cakes to at least partially solidify during said movement so as to permit their continuous discharge at said discharge point in substantially solid form.

3. The improvement in the production of sulphur by underground fusion with the discharge of molten sulphur at the surface of the ground, which comprises continuously forming the sulphur while still in a molten state into a plurality of relatively small thin cakes, moving said cakes in a substantially continuous manner from the point of their formation to a discharge point, allowing the cakes to only partially solidify during said movement and discharging them at said discharge point while the sulphur in the interior of the cakes is still molten, continu-v ously moving the partially solidified cakes to a second discharge point, and allowing the cakes to completely solidify before being discharged at said second discharge point.

4. The improvement in'the production of sulphur by underground fusion with the discharge of molten sulphur at the surface of the ound, which com rises continuously forming the sulphur while still in a molten state into a plurality of relatively small thin cakes, moving said cakes in a substantially continuous manner from the point of their formation to a discharge point, and subjecting the cakes during said movement to the action of a cooling medium for promoting the solidification thereof, and continuously discharging the cakes at said discharge point in substantially solid form.

5. The improvement in the production of sulphur by underground fusion with the discharge of molten sulphur at the surface of the ground, which com rises continuously pouring the sulphur whi e still in a molten state into a plurality of relatively shallow metal pockets, the sulphur-contacting surfaces of said pockets being first moistened with an appropriate liquid to prevent sticking of the molten sulphur thereto, moving said cakes in a substantially continuous manner from the point of their formation to a discharge point, and allowing the cakes to at least partially solidify during said movement so as to permit their continuous discharge at said discharge point in substantially solid form.

6. The improvement in the production of sulphur by underground fusion with the discharge of molten sulphur at the surface of the ground, which comprises continuously forming the sulphur into cakes by pouring the sulphur while still in a molten state into a plurality of relatively shallow pockets which become so filled that the molten sulphur overflows the pockets and forms a relatively thin layer of sulphur overlaying a plurality of the sulphur-filled pockets, moving said cakes in a substantially continuous manner from the point of their formation to a discharge point in the course of which movement the interconnection between the cakes promotes the loosening of the cakes from their respective forming pockets, and allowing the cakes to at least partially solidify during said movement so as to permit their continuous discharge at said discharge point in substantially solid form.

7. The improvement in the production of sulphur by underground fusion with the discharge of molten sulphur at the surface of the ground, which comprises continuously forming the sulphur while still in a molten state into a plurality of relatively small thin cakes weighing approximately three pounds each, moving said cakes in a substantially continuous manner from the point of their formation to a discharge point at the rate of about fifteen feet per minute, allowing the cakes to only partially solidify during said movement and discharging them at said discharge point before the sulphur in the interior of the cakes is completely solidified, moving the partially solidified cakes to a second discharge point, and allowingJ the cakes to completely solidify before emg discharged at said second discharge point.

In testimony whereof I aflix my signature.

ROBERT HOLDEN STEWART. 

